On Xcode 4.3.1 4E1019, Launch screen (Default.png, etc) has white line (1 pt tall) at bottom of image on launch

Question

This is odd. I have a Default.png, Default-Landscape.png, Default-Portrait.png and Default@2x.png.

The normal "default screen zoom animation" is where the Default.png zooms from the center of the screen out "into" place. This happens with all apps on iOS so this is the time when you can really see that white-line on the bottom of the "Default" image. It is a 1 pt (or so) line, going from left-to-right at the bottom of all my Default.png's (Default@2x.png, Default-Landscape.png, etc)... It occurs on both of my devices: "iPhone 4" and "iPad 1". It does NOT occur on any of the simulators.

The images have not changed between my builds. Indeed, last week I built an earlier version (with the same launch graphics) and this did not happen.

The images are the correct size. I even changed the .ipa to a .zip, uncompressed and looked in the package. The pngs are the correct size, so nothing killed that.

When I revert back to the AdHoc from the last build of my app, the issue goes away. When I move to the current build, the issue comes back.

Any ideas?

BTW: Addendum: I grabbed my old source code (for the version that is okay), compiled with Xcode 4.3.1 and have the same issue. white line on the bottom of the launch screen.

Addendum

Okay, well one thing we noticed:

Our PNGs for ipad were 1024x768 and 768x1024 instead of 1004x768 and 748x1024

We fixed that (weird that they worked before) and iPad launch was fixed and displays properly. iPhone is still broken.

the iOS Human Interface Guidelines/ Custom Icon and Image Creation Guidelines says iPhone are supposed to be 320x480 and 640x960

I must've gotten confused when i originally created iPad graphics, but they have been working up until XCode 4.3.1!!! (2 years!) I know my iPad sizes were off, but wonder what made XCode change this and decide they were borked now?

Answer 1

This is the same issue as: iOS 5.1 : -[UIColor colorWithPatternImage:] background color draws solid black

Basically: iOS 5.1 fails to decode the last line of pixels in an indexed-color PNG (PNG8) or any grayscale PNG.

The workaround is to use PNG32, or add dummy lines to the end of the PNG8.

I filed a bug with Apple (#11069678) and advise you to do the same :)

Answer 2

Photoshop users:

• Use the Image menu to change the mode to RGB.
• Then use the Image menu to switch to 16 Bits/Channel.